Feed bar for soft leather working machine



Oct; 20, 1959 P. A. BLATZ FEED BAR FOR SOFT LEATHER WORKING MACHINE Filed May '24, 1957 INVENTOR P6 1161" A .5 lat Z ATTORNEYS P -Uni 7 United States Patent iiC 2,909,008 Patented Oct. 20, 1959 FEED BAR FOR SOFT LEATHER WORKING MACHINE Peter A. Blatz, Wilmington, Del., assignor of one-third each to Ellen B. Jenkins, La Grange, 11]., May B. Simon, Hendersonville, NC, and Elizabeth B. Kane, Kaolin-Avondale, Pa.

Application May 24, 1-957, Serial No. 661,428

8 Claims. (Cl. 51-78) This invention relates to a pressure finger member for a soft leather working machine, and more particularly relates to an improved pressure finger member for a machine for shaping and buffing soft pliable skin leather.

A pressure finger member for a soft leather working machine is described and claimed in US. Letters Patent 2,758,425. This member is associated with a rotating working cylinder and a feed roll, and it cooperates with the feed roll to feed the leather smoothly through the machine. As a result of the action of this member, deleterious edge cutting of the skins has been remarkably reduced; but its occurrence has not been entirely eliminated,-particularly when thin soft skins are being fed.

An object of this invention is to provide an improved pressure finger member for a soft leather working machine which eliminates edge cutting to a greater extent than that heretofore achieved, particularly when thin- The passage of any irregularities or wrinkles is thereby restrained, and the leather passing out of the throat is I maintained substantially free of wrinkles.

Coincident contacting surfaces of considerable extent provide a maximum number of continuous opposing contacting surface elements. However, since the feed roll wears and decreases in diameter over its useful life, only a compromise with absolute coincidence at all times can be achieved. However, as long as the tip of the pressure vfinger member is maintained in firm contact with the feed roll. and the surface element of the pressure finger member at the entrance to the confined throat is maintained in reasonably firm contact with the feed roll,

. adequate restraint upon feeding leather is provided An adequate compromise is provided, for example, by shaping the contacting surface of the pressure finger member to correspond to the average radius of curvature of the 0 feed roll as it wears down over its useful life.

A member of the type described may be resiliently and rotatably mounted from the stationary frame of the machine to permit it to automatically maintain optimum contact relationship with the feed roll as its diameter wears and decreases over its useful life. Stops for limitingthe travel of the member towards the workingcylinder and feed roll may be provided to respectively prevent its contact with the rough surface of the working cylinder and to prevent it from following the feed roll a consider- .able distance as the feed roll is withdrawn from its Working orskin-engaging position.

Novel features and advantages of the present invention will become apparent to one skilled. in the art from a reading of the following description in conjunction with 2 the accompanying drawing in which similar character references refer to similar parts and in which:

Fig. 1 is a view in elevation of an embodiment of this invention;

; Fig. 2 is a cross-sectional view'taken through Fig. 1 along the line 2'2 and looking in the direction of the arrows; and

Fig. 3 is an enlarged cross-sectional view ofa the embodiment shown in Fig. 1.

Figs. 1 and 2 show a pressure finger assembly 10 operatively associated with portions of a soft leather working machine 12 of the general type described in US. Letters Patent 2,305,789 and 2,758,425. Soft leather working machine 12 includes a stationary frame 14 upon which feed roll 16 and working or buffing roll 18 are mounted .on substantially parallel axes. Assembly 10. includes a mounting structure 20 and a pressure finger member 22. Pressure finger member 22, as described and claimed in US. Letters Patent 2,758,425, contacts the surface of the .feed roll 16 a short distance from the nip between the working cylinder and the feed roll 16. In US. Letters Patent 2,758,425 contacting end 24. of the feed bar 10 or pressure finger member 22 engages the surface of feed roll 16 with substantially line contact. This is broad- .ened to some extent by the, pressure ofthe end 24 into the resilient or rubber covered surface of the feed roll to a band approximately /a of an inch in width, but must still be described as substantially line contact. In Figs. 1 and 2, however, end 24 includes a surface 26 extending from line 25 to line 27, which are shown as vcorresponding points 25 and 27 in cross-sectional Figs. 1 and 3. This surface 26 is of considerable extent in the direction of movement of the surface of the feed roll 16 and substantially coincides with the portion of the surface 0f feed roll 16 which it contacts. Since the resilient or rubber surface of feed roll 16 wears down considerably over its useful life, the radius of curvature of contacting .surface or contacting end 26 of pressure finger member 22 is arranged, for example, to correspond to the average radius of curvature of feed roll 16 as it wears over its useful life. f

The outermost circumference 17 of feed roll 16 shown in Figs. 1 and 3 represents a substantially unworn roll. The radius of curvature of surface 26 is, therefore, slightly smaller than the radius of curvature of outer circumference 17. The radius of curvature of circumference 17 of a substantially new feed roll 16, for example, is approximately 3% inches, and it wearsdown during its useful life to a radius of curvature of approximately 2 /2 inches. In Fig. 3 the minimum circumference having a radius of curvature, for example, of 2 /2 inches is designated by circle 19, and an approximately average cirportion of .cumference having a radius of curvature of 3% inches .is designated by circle 21. A radius of curvature of 3% inches for surface 26., therefore, provides an emcientcoinpromise over the useful life of an illustrative feed roll 16. For this radius of curvature contacting surface 26 is approximately 1 /2 inches in cross-sectional length.

Pressure finger member 22 slopes away from the surface of feed roll 16 at contacting .line or point 27. This provides a convergi-ngthroat for feeding leather into the confined space or throat-between surface 26, and the surface of feed roll 16. .Thebody of pres-sure finger member has, for example, a radius of curvature slightly greater'than the radius ofcurvature of feed roll 16,, for example, approximately 4 inches, and it is: arranged at ,an angle thereto which maintains surface 26in contact \with r011 16 and provides the aforementioned converging throat leading into the. confined space .or throat between the contacting surfaces. I v 7 Rotatable means, for example, are providedfonsupporting mounting assembly 10 from frame 1 4'. This retatable means includes, for example, cylindrical shafts 28 extending from either side of structure which are rotatably inserted within bearings 30 supported upon frame 14. Elastic means 32, for example, are provided for resiliently urging pressure finger member 22 into contact with the surface of feed roll 16. Elastic means 32 includes, for example, compression springs 34 which react between plates 36 welded to mounting structure 20 and corresponding bars 38 mounted substantially parallel to plates 36 by bolts 39 upon a portion of frame 14, for example, upon the housings of bearings 30. Cap screws 40 are engaged in bar 38 and extend through compression springs 34 to retain and guide them in their reaction against the plates 36.

A predetermined clearance 37 is provided between the bottom 42 of cap screws 40 and the upper surfaces of plates 36. Cap screws 40 are, for example, backed off a quarter of a thread from contact with base 36 to permit springs 34 to react against plates 36 and to provide a. limit of travel of pressure finger member 22 towards working cylinder 18. This clearance is, for example, approximately 1 inch. This amount of movement is not great enough to allow member 22 to be forced against the rough surface of the working cylinder, for example, by irregularities in the leather being fed.

A stop means for limiting the resilient travel of pressure finger member 22 in the other direction is provided by cap screws 44 engaged in the rear of bar 38. The extent of resilient travel or rotation of pressure finger member 22 towards feed roll 16 is limited by the distance or clearance 41 between the bottoms 46 of cap screws 44 and the upper surface of plate 36. This movement is limited, for example, to approximately inch to prevent member 22 from following the feed roll 16 for too great a distance each time the feed roll is withdrawn from its working and skin-engaging position.

Operation When feed roll 16 is moved forward into its working or leather engaging position relative to working cylinder 18 it automatically moves into contact with surface 26 of pressure finger member 22. It, therefore, rotates mem ber 22 and bar 36 away from end 46 to stop screw 44 to provide the predetermined z inch clearance 39 between the end 46 of stop screw 44 and bar 36 and simultaneously compresses spring 34 which then maintains member 22 in resilient contact with feed roll 16. End or tip of surface 26 is thereby maintained in firm engagement with 'the surface 17 of a new feed roll 16 and surface element 27 at the entrance to the confined throat is maintained in reasonably firm contact with the surface 17 of a new or unworn feed roll 16. In this condition a narrow throat of considerable length in the direction of movement of surface of roll 16 or in the direction of movement of leather 'being fed is provided between surface 26 and surface 17 strained therein and the leading end of the leather is smoothly passed out under the tip of the pressure finger member 22. The body of member 22 which slopes away from the surface of feed roll '16 provides a convergent throat which feeds the leather smoothly into the confined or smoothing throat. Adequate restraint is provided throughout the entire length of the throat when firm contact is provided at tip 25 and at point or line 27.

7 When feed roll 16 wear-s down to its approximate average size designated by circle 21 (Fig. 3) which has a radius of approximately 3% inches, surface 26 substan- ,tially coincides therewith to provide a confined throat of .optimum coincidence and efficiency.

When feed roll 16 wears down to its minimum useful size designated by circle 19 (Fig. 3) which is approximately 2 /2 inches in radius, the elasticity of the skin and the surface of the feed roll permit surface 26 to substantially coincide therewith. Although the radius of curvature of surface 26 is longer than the radius of curvature of circle 19, element 27 can still be maintained in reasonably firm contact with the feed roll 16 to provide adequate restraint throughout the entire length of the throat.

Pressure finger member 22 remains in the illustrated position relative to working cylinder 18 as roll 16 iscontinually moved forward towards working cylinder 18 as its surface wears down and decreases in radius. The rotatable and resilient mounting of assembly 10, however, permits pressure finger member 22 to automatically conform to the changing circumference of the feed roll 16 as it wears. Substantially no manual adjustment of pressure finger 22 is, therefore, necessary over the useful life of feed roll 16.

What is claimed is:

1. In a soft leather-working machine including a working cylinder and a feed roll rotatably mounted upon a stationary frame a working distance apart on substantially parallel axes, a leather-feeding throat comprising a pressure finger member inserted between said working cylinder and said feed roll with its end contacting the surface of said feed rolla short distance from the nip between said working cylinder and said feed roll, said contacting end of said pressure finger member including a leather-contacting surface of considerable length in the direction of movement of the surface of said feed roll, said leathercontacting surface having a radius of curvature substantially equal to the average radius of curvature of said feed roll as it wears down over its useful life and being disposed in contact with said surface of said feed roll to provide a confined narrow throat therebetween, the body of said pressure finger member being constructed and arranged to slope away from the surface of said feed roll when said leather-contacting surface is maintained in engagement therewith to provide a convergent throat for feeding leather to said confined narrow throat, and supporting means for said pressure finger member which maintains said leather-contacting surface of said pressure finger member in firm contact with the surface of said feed roll throughout the length of said confined narrow throat.

2. A leather-feeding throat as set forth in claim 1 wherein the radius curvature of said leather-contacting surface is approximately 3% inches whereby it provides said confined narrow throat in conjunction with said feed roll as the radius of curvature of said feed roll wears down over its useful life from approximately 3% inches to 2 /2 inches.

3. A leather-feeding throat as set forth in claim 2 wherein the radius of curvature of the body of said pressure finger member is greater than the radius of curvature of said feed roll.

4. A leather-feeding throat as set, forth in claim 3 wherein the radius of curvature of the body of said pressure finger member is approximately 4 inches.

5. A leather-feeding throat as set forth in claim 1 wherein said supporting means includes rotatable means operatively coupling said pressure finger member to said frame, and a resilient means reacts between said frame and said supporting means in a direction to urge said leather-contacting surface of said pressure finger member into firm resilient contact with the surface of said feed roll. 7

6. A leather-feeding throat as set forth in claim 5 wherein motion-limiting means are provided between said roltatable means and said frame, said motion limiting means including a first stop disposed in the direction of movernent of said rotatable means towards said working cylinder, and said motion-limiting means including a second stop disposed in the direction of movement of said pressure finger member towards said feed roll.

7. A leather-feeding throat as set forth in claim 6 where in said pressure finger member is rotatably mounted upon said frame by means of shaft and bearing means, said first stop means being provided by a first screw member to provide adjustment thereof and said resilient means is com prised of a compression spring mounted about said screw.

8. A leather-feeding throat as set forth in claim 7 wherein said second stop means is provided by a second screw member to provide adjustment thereof.

References Cited in the file of this patent UNITED STATES PATENTS Leach Dec. 22, 1942 FQREIGN PATENTS Germany June 21, 195 1 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,909,008 October 20, 1959 Peter A. Blatz It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 line 43 for "to stop" read of stop column 4, line 47 after "radius. insert of Signed and sealed this 28th day of June 1960.,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

